function [x sign] = signal2(step)
x = -5:step:7;
alpha = 2;
sign = zeros(1,length(x));
for k = 1:length(x)
    if (x(k)>=-1) && (x(k)<=alpha/2)
        sign(k) = 1-abs(x(k));
    elseif (x(k)>alpha/2) && (x(k)<=alpha+1)
        sign(k) = 1-abs(x(k)-alpha);
    else sign(k)=0;
    end;
end;


